‘Though their causes be not yet discover’d’: occult principles in the making of Newton’s natural philosophy

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Henry, John

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Ahnert, Thomas

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Wang, Xiaona

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2019-07-24T16:15:28Z

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2019-07-24T16:15:28Z

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2019-07-08

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http://hdl.handle.net/1842/35857

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This thesis aims to provide a fuller understanding of a highly important but still
controversial aspect of Isaac Newton’s natural philosophy: the role of occult, or at
least non-mechanical, principles in his natural philosophy. The most obvious of these
was his belief that gravity was an attractive force which operated across empty space,
and so was an occult actio in distans. But there are other aspects of Newton’s work
which would have been regarded by Cartesian contemporaries as occult; such as his
belief that light can be an active component within bodies, that light and other matter
can be converted into one another, and that bodies are not inert and passive but
manifest various principles of activity. R. S. Westfall, suggested in the 1970s that
Newton’s unprecedented success as a natural philosopher was due to the fact that he
combined two seemingly antithetical traditions of natural knowledge, the mechanical
tradition, and what he called the Hermetic tradition. This thesis replaces Westfall’s
outdated notion of a “Hermetic” tradition with broader occult or natural magical
traditions and shows how they formed the context within which Newton’s own work
was formed. The thesis is not primarily a study of Newton’s work but a study of the
work of earlier English thinkers who can be seen to have established the occult
traditions which were subsequently taken up by Newton. Each chapter, therefore,
focuses on a different aspect of occult ways of thinking in natural philosophy during
the early modern period, and finally shows, in the conclusion to each chapter, how
these ideas appeared in Newton’s work, and, as Westfall suggested, contributed to
his unprecedented success. Over six chapters the thesis considers theories that the
world system is a network of radiating forces analogous to light rays, that gravity is
an attractive force analogous to magnetism and operates at a distance, that matter has
the power to attract and repel other matter, or has the power to incessantly emit
active material effluvia, or the power to vibrate. It also shows how beliefs about the
mathematical principles of natural philosophy, and the usefulness of the
experimental method made possible, and supported, these theories about occult
principles.
The focus is on English thinkers and developments in English natural philosophy.
This is not just an arbitrary choice but reflects sympathetic attitudes to occult ways of
thinking in English thought which are shown to derive from the first natural
philosophers in England to acquire international reputations since the Middle Ages,
John Dee, Francis Bacon, and William Gilbert. Writing before the mechanical
philosophy was conceived, these three thinkers all embraced occult ideas and left
them as a legacy for subsequent English thinkers, up to and including Newton. The
thesis shows that the combination of occult and mechanical traditions discerned in
Newton’s work by Westfall was in fact highly typical of English thinkers who
combined occult ideas deriving from Dee, Bacon, and Gilbert, with the emerging
mechanical philosophy. This marked trend in English natural philosophy reached its
culminating point in the work of Newton, but Newton’s achievement was only
possible because of what had gone before. The thesis shows, therefore, that
Newton’s achievement crucially depended upon this English background.